SOUTH HADLEY — Diana L. Bonneville of Becket, principal of Hopkins Academy in Hadley since 2007, has been chosen as principal of South Hadley High School.

Nicholas D. Young, school superintendent, announced Thursday afternoon he had chosen Bonneville to lead what he has termed “South Hadley’s flagship school.”

Bonneville and Edward “Ted” McCarthy of Amherst, SHHS assistant principal since 2010, were the two finalists publicly interviewed for the position on Tuesday by the School Committee in the high school library before about 40 onlookers. Young said the position drew 31 applicants.

The new principal replaces Sean McNiff of Shutesbury, who resigned unexpectedly in August after a year on the job. Veteran educator Christine Sweklo, who was acting superintendent after former superintendent Gus A. Sayer retired in January, is now SHHS acting principal.

The school superintendent said he will negotiate the new principal’s pay and start date with Bonneville next week. He said he contacted Hadley interim school Superintendent Donna Moyer on Thursday and asked that Bonneville be released from her contract as Hopkins Academy principal so she could start at SHHS in early December.

“She promised me that she would do her best,” Young said of Moyer.

Moyer could not be reached for comment Thursday, but Hadley School Committee Chairwoman Robie Grant said the Hadley school chief plans to “immediately” advertise for Bonneville’s interim replacement.

“We’ll be launching a search for a permanent replacement in the spring,” Grant said of the Hadley school board.

Young said the South Hadley post will pay between $100,000 and $110,000 a year. Because Bonneville has more than 12 years experience as an administrator, “she’s going to be on the high end of the scale,” he said.

Bonneville now makes about $97,500 as head of Hopkins Academy, founded as a private school in 1664 and considered one of the best public schools in the country. It was chosen as a top school in 2010 by U.S. News and World Report and as one of the top in the state by the Boston Globe in 2008.

Bonneville has a master’s degree in education from Westfield State University and is completing a doctorate in education at the University of Massachusetts Amherst.

Young said Bonneville’s success in raising academic achievement at the 315-student school was a major reason for his decision to bring her to the 670-student South Hadley High.

“Mrs. Bonneville and I worked very well together to build academic achievement,” said Young, who headed Hadley schools for 11 years before taking the job as South Hadley school chief this year. “I want to replicate that success in South Hadley,” he added.

“I think Diana Bonneville will bring the experience and expertise that South Hadley High School needs,” said Barry C. Waite, chairman of the South Hadley School Committee. Before becoming principal of Hopkins Academy, Bonneville was an assistant principal in Northampton public schools from 2000 to 2007 and as a social studies teacher at the Southern Berkshire Regional School District in Sheffield from 1995 to 2000.

She is the second Hadley educator to follow Young to South Hadley. He has already hired former Hopkins Academy athletic director Patrick Lemieux as SHHS assistant principal, replacing William Evans, who is now principal of North Brookfield High School

Both Waite and Young praised McCarthy, the other finalist.

“I admire Mr. McCarthy a great deal,” said Waite, adding he hopes to keep the educator in the South Hadley school system.

Young called McCarthy “a formidable candidate” for the principal’s position,” but said he opted for Bonneville because she has more administrative experience. McCarthy served as chairman of the SHHS special education department from 2005 to 2010, before becoming assistant principal. He was head teacher at the Hampshire Educational Collaborative in Northampton from 1996 to 2005.

“It was not one of the easier decisions I’ve made in my career,” Young said. “Ultimately, it turns out that this is the best of both worlds because they will both be working at the high school.”